FIGS. 20(a), 20(b) show a structure disclosed in a Patent Document 1, the reference numeral 21 represents a pull-in unit (sliding-door closer) attached to the upper side of a frame of an opening portion on a main body side, and the reference numeral 3 represents an operational member (engagement pin) provided on a sliding-door side which is the moving body. The pull-in unit 21 comprises a case 22, a hook member 36, urging means 35 and the like. The case 22 has a shape of a short container, and forms an engagement groove portion 25 extending in a longitudinal direction from one end side, and a sliding groove portion 31 (comprising a linear movement groove portion 32 and a rotational groove portion 33 which is folded back on one end side of the movement groove portion 32). The hook member 36 forms a retaining concave 46 disengaging the operational member 3 and engagement convexes 44, 45 which fit into the sliding groove portion 31. The urging means 35 urges the hook member 36 to the other end side of the sliding groove portion 31 in the state wherein one end of the urging means 35 is held in the hook member 36, and the other end of the urging means 35 is held in a case 22 side. The urging means 35 stores an urging force while a sliding door is slid from a closed direction to an open direction. The operational member 3 is attached to be swingable along a sliding hole 8 of a plate 5 and to be returnable due to an urging force (not shown) through an automatic return mechanism 4 relative to the upper end face of the sliding door.
In the above-mentioned structure, as shown in FIG. 20(a), the operational member 3 is moved toward the pull-in unit 21 on a main body side due to a closing operation of the sliding door. Then, the operational member 3 is fitted into the engagement groove portion 25, and after sliding along the engagement groove portion 25, as shown in FIG. 20(b), the operational member 3 is engaged with the retaining concave 46 of the hook member 36 and retained thereat. In this process, after the engagement convex 44 is rotated as a center of the engagement convex 45 while being guided by the rotational groove portion 33 of the sliding groove portion 31, and moved from a stand-by position to a pull-in position, the hook member 36 is fitted into the movement groove portion 32. Due to this engagement, the hook member 36 is slid toward the back end side of the case 22 by the urging force of an urging means 35 while holding the operational member 3, and completely pulled in. Also, from the above-mentioned state, due to an opening operation of the sliding door, the operational member 3 is slid to a front end side of the case 22 with the hook member 36, and stores an urging force to the urging means 35. Further, when the sliding door is opened, due to a returning operation of the operational member 3 through the automatic return mechanism 4, the engagement convexes 44 is moved to the rotational groove portion 33 from the movement groove portion 32, so that the hook member 36 is switched to the stand-by position in FIG. 20(a).
Incidentally, Patent Document 2 discloses a structure having a buffer member which creates a frictional force by being pushed by an operational member (stopper pin), as a braking mechanism which decreases speed of the sliding door, as well as the above-mentioned pull-in unit. This braking force is created separately from a rotary damper by a force wherein the operational member presses the buffer member inside the case, and increases in proportion to the increase of the speed of the sliding door.
Patent Document 1: Japanese Unexamined Patent Application Publication (TOKKAI) No. 2005-290769
Patent Document 2: Japanese Unexamined Patent Application Publication (TOKKAI) No. 2007-16521